diff --git a/js/src/jsapi.h b/js/src/jsapi.h
index 4944cf79be5..05a9f898d19 100644
--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -1644,7 +1644,7 @@ JS_SetNativeStackQuota(JSContext *cx, size_t stackSize);
  * Set the quota on the number of bytes that stack-like data structures can
  * use when the runtime compiles and executes scripts. These structures
  * consume heap space, so JS_SetThreadStackLimit does not bound their size.
- * The default quota is 32MB which is quite generous.
+ * The default quota is 128MB which is very generous.
  *
  * The function must be called before any script compilation or execution API
  * calls, i.e. either immediately after JS_NewContext or from JSCONTEXT_NEW
@@ -1653,7 +1653,7 @@ JS_SetNativeStackQuota(JSContext *cx, size_t stackSize);
 extern JS_PUBLIC_API(void)
 JS_SetScriptStackQuota(JSContext *cx, size_t quota);
 
-#define JS_DEFAULT_SCRIPT_STACK_QUOTA   ((size_t) 0x2000000)
+#define JS_DEFAULT_SCRIPT_STACK_QUOTA   ((size_t) 0x8000000)
 
 /************************************************************************/
 
diff --git a/js/src/xpconnect/src/xpcjsruntime.cpp b/js/src/xpconnect/src/xpcjsruntime.cpp
index 462249da751..b1d9d7cc68e 100644
--- a/js/src/xpconnect/src/xpcjsruntime.cpp
+++ b/js/src/xpconnect/src/xpcjsruntime.cpp
@@ -47,6 +47,7 @@
 #include "jsgcchunk.h"
 #include "nsIMemoryReporter.h"
 #include "mozilla/FunctionTimer.h"
+#include "prsystem.h"
 
 /***************************************************************************/
 
@@ -1313,7 +1314,9 @@ XPCJSRuntime::OnJSContextNew(JSContext *cx)
         return JS_FALSE;
 
     JS_SetNativeStackQuota(cx, 128 * sizeof(size_t) * 1024);
-    JS_SetScriptStackQuota(cx, 25 * sizeof(size_t) * 1024 * 1024);
+    PRInt64 totalMemory = PR_GetPhysicalMemorySize();
+    JS_SetScriptStackQuota(cx, PR_MAX(25 * sizeof(size_t) * 1024 * 1024,
+                                      totalMemory / 4));
 
     // we want to mark the global object ourselves since we use a different color
     JS_ToggleOptions(cx, JSOPTION_UNROOTED_GLOBAL);